Well, I've shot a lot of 1K BR, but not F-class. I've used a 24, a 36, and a (Nightforce) variable. I think Al has it just right. If you can afford the weight and dollars, it is hard to beat a variable. If you're going fixed power, hard to beat a 24X.
The interesting scope if you're a bit budget-minded is the Sightron 10-50x60mm. There have been a few negative comments (at least, early on), and a number of raves, too. Always hard to know how well something holds point-of-impact, the thing that matters most. Of course at close the $1,000, it is a lot more than a good 24, either a Weaver, or older Leupold.
I've never worried over much about clarity -- we shoot in good light, after all, But the Sightron is quite clear.